Checking The First Step Of Servo (1)3-6; Checking The Second Step Of Servo (2) - LG GoldStar DVD5185 Service Manual

9. Checking the first step of servo (1)
Let's look over the initial step of DSP
1) First. DSP IC receive the DSP - Reset from
CPLD
2) This reset signal get DSP initialized and DSP is
ready to do first step for servo
3) TSTSG from DSP is the test signal for checking
the PLL- loop
4) RF IC regard this test signal as RF signal which
is coming from P/up and send this signal to
IC201
DSP IC
47
110
DSP-RST
IC502 IC202
CPLD RF IC

10. Checking the second step of servo (2)

Let's look over the initial step of servo
1) when the tray is closed, first of all, it should be
checked whether there is disc or not on tray
2) CD laser is turn on and the lense is moved. if
there is a disc on tray, RF signal will appear
3) next, it should be confirmed which disc is that.
CD or DVD.
M/D
ASSY
CN201
LD-DVD
IC202
RF IC
Vcc(3.3V)
Reset period
82
DSP-RST
TSTSG
TSTSG
move lense
1) ~ 2)
DSP. DSP perform the procedure of PLL-loop
by using this signal.
5) after checking the PLL-loop, the second step is
followed. the second step will be explained on
next page.....
if TSTSG doesn't appear, check DSP and
replace. if the unit doesn't work normally, even
though the both signals are OK.Check the RF
IC and replace.
4) the following step will be done continuously CD -
Laser on -> move lense -> DVD - laser on ->
move lense. in according to disc type, there will
be RF signal...
5) after confirming disc, CD or DVD laser turn on
and focus servo is executed...
the below picture is related signals when DVD
disc is inserted
CD laser on
3-6
720 Khz 4.3 Mhz
F+
CD/DVD
DVD laser on
LD-CD
LD-DVD
4) 5) 6)